Electrosurgical devices with wire electrode

ABSTRACT

The invention provides an electrosurgical device and methods of use thereof. In one embodiment, the device may comprise a handle, a shaft distal to the handle, a first electrode tip and a second electrode tip adjacent a distal end of the shaft, with the first electrode tip spaced from the second electrode tip and wherein the first electrode tip comprises a first U-shaped electrode and the second electrode tip comprises a second U-shaped electrode, and at least one fluid outlet. In another embodiment, the device may comprise a handle, a shaft distal to the handle, and a first electrode and a second electrode adjacent a distal end of the shaft with the first electrode coplanar with the second electrode and comprising a wire electrode having a U-shape which surrounds a perimeter of the second electrode and is spaced from the second electrode by an aperture.

FIELD

This invention relates generally to the field of medical devices, systems and methods for use upon a human body during surgery. More particularly, the invention relates to electrosurgical devices, systems and methods that provide for cutting of tissue in addition to coagulation, hemostasis and sealing of tissue to inhibit blood and other fluid loss during surgery such as abdominal, orthopedic, head, spine and thoracic surgery as well as general surgery of the body.

BACKGROUND

Fluid-assisted electrosurgical devices have been developed which, when used in conjunction with an electrically conductive fluid such as saline, may be moved along a tissue surface, without cutting the tissue, to seal tissue to inhibit blood and other fluid loss during surgery. However, to cut tissue the surgeon must utilize a second device, which necessitates delays associated when switching between devices. What is still needed is an electrosurgical device which is capable of cutting of tissue as well as providing fluid-assisted sealing of tissue to inhibit blood and other fluid loss during surgery, as well as inhibit undesirable effects of tissue desiccation, tissue sticking to the electrode, tissue perforation, char formation and smoke generation. What is also needed is an electrosurgical device which cuts tissue with reduced lateral thermal spread and damage to adjacent tissue.

SUMMARY OF THE INVENTION

The invention, in one embodiment, may provide an electrosurgical device to treat tissue in a presence of a fluid from a fluid source and radio-frequency power from a radio-frequency power source, particularly providing a bipolar power output and a monopolar power output. The device may comprise a distal portion comprising a first electrode tip, a second electrode tip and at least one fluid outlet. The first and second electrode tips may be configured as bipolar electrodes, configured to receive the bipolar power output from the radio-frequency power source to treat tissue, particularly by moving along a tissue surface in a presence of a bipolar power output and a fluid provided simultaneously from the distal portion. At least one of the electrode tips may be configured as a monopolar electrode, configured to receive the monopolar power output from the radio-frequency power source and provide an electrosurgical cutting edge, which may be configured to cut tissue by moving along a tissue surface in a presence of monopolar power output provided from the distal portion.

In certain embodiments, the electrosurgical device may comprise a handle, a shaft distal to the handle, a first electrode tip and a second electrode tip adjacent a distal end of the shaft, with the first electrode tip spaced from the second electrode tip and wherein the first electrode tip comprises a first wire electrode having a U-shape and the second electrode tip comprises a second wire electrode having a U-shape, and at least one fluid outlet.

Each of the first and second U-shape electrodes may comprise an arcuate distal segment and two longitudinal segments extending distally relative to a distal end of the shaft. The arcuate distal segment of each of the first and second U-shape electrodes may be arcuate from one longitudinal segment to the other longitudinal segment, and may be semicircular between the two longitudinal segments. At least one of the U-shape electrodes may provide a cutting edge, which may be an electrosurgical cutting edge and may be arranged along a longitudinal length of the U-shape electrode. The cutting edge may particularly be straight (linear).

The first electrode and a second electrode may be formed from metal wire. The metal wire may be single strand (solid core) wire, and more particularly circular single strand wire. The metal wire may be stainless steel wire. In this manner, the electrodes may have a low mass, which may allow the electrodes to dissipate heat and cool quickly during and after tissue treatment, which may inhibit damage to adjacent tissue (not to be treated) due to lateral thermal spread.

The at least one fluid outlet may be located a distal end of the shaft. More particularly, the fluid outlet may be located between the two longitudinal segments of at least one of the U-shape electrodes.

The at least one fluid outlet may comprise a first fluid outlet and second fluid outlet. The first fluid outlet may be located between the two longitudinal segments of the first U-shape electrode, and the second fluid outlet is located between the two longitudinal segments of the second U-shape electrode.

The U-shape electrodes may be coplanar. The two longitudinal segments of the first U-shape electrode and the two longitudinal segments of the second U-shape electrode may be parallel, and more particularly in a single plane.

One longitudinal segment of each of the first and second U-shape electrodes may be a medial longitudinal segment and the other longitudinal segment may be a lateral longitudinal segment.

The two longitudinal segments of the second U-shape electrode may be medial relative to the two longitudinal segments of the first U-shape electrode.

The first U-shape electrode may surround a perimeter of the second U-shape electrode, and the second U-shape electrode may be located within a U-shape aperture defined by the first U-shape electrode.

Each of the first and second U-shape electrodes may comprise an arcuate distal segment, and the arcuate distal end segments may be concentric.

The first U-shape electrode and the second U-shape electrode may have at least one of a same size and a same shape, and a position of first U-shape electrode and a position of the second U-shape electrode may be fixed relative to one another.

In certain embodiments, the electrosurgical device may comprise a handle, a shaft distal to the handle, a first electrode tip and a second electrode tip adjacent a distal end of the shaft, with the first electrode tip spaced from the second electrode tip and wherein the first electrode tip comprises a first electrode having a first arcuate wire portion forming an arc of at least 180 degrees and the second electrode tip comprises a second electrode having a second arcuate wire portion forming an arc of at least 180 degrees, and at least one fluid outlet.

In certain embodiments, the electrosurgical device may comprise a handle, a shaft distal to the handle, and a first electrode and a second electrode adjacent a distal end of the shaft with the first electrode coplanar with the second electrode and comprising a wire electrode having a U-shape which surrounds a perimeter of the second electrode and is spaced from the second electrode by an aperture. In certain embodiments, the second electrode may comprise a wire electrode having a linear segment, a U-shape or a blade shaped member. The device may also comprise at least one fluid outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of one embodiment of a system of the present invention having an electrosurgical unit in combination with a fluid source and handheld electrosurgical device;

FIG. 2 is a front perspective view of the electrosurgical unit of FIG. 1;

FIG. 3 is a graph of the bipolar RF power output versus impedance for the electrosurgical unit of FIG. 1;

FIG. 4 is graph showing a relationship of fluid flow rate Q in units of cubic centimeters per minute (cc/min) on the Y-axis, and the RF power setting P_(S) in units of watts on the X-axis;

FIG. 5 is a perspective view of an electrosurgical device according to the present invention;

FIG. 6 is a plan view showing the various electrical connections and conductors of the device of FIG. 5 with the electro surgical unit of FIG. 1;

FIG. 7 is a plan view showing a first embodiment of the various fluid connections and passages of the device of FIG. 5 with the electrosurgical unit and fluid source of FIG. 1;

FIG. 8 is a plan view showing a second embodiment of the fluid connections and passages of the device of FIG. 5 with the electrosurgical unit and fluid source of FIG. 1;

FIG. 9 is a close-up view of the shaft of the device of FIG. 5;

FIG. 10 is a close-up cross-sectional view of the electrodes of the device of FIG. 5. taken along line 10-10 of FIG. 5;

FIG. 11 is a close-up cross-sectional view of another embodiment of the electrodes of the device of FIG. 5 taken along line 10-10 of FIG. 5;

FIG. 12 is a close-up cross-sectional view of another embodiment of the electrodes of the device of FIG. 5 taken along line 10-10 of FIG. 5;

FIG. 13 is a perspective view of the device of FIG. 5 cutting tissue;

FIG. 14 is a close-up view of a distal end portion of the device of FIG. 5 with an exemplary fluid coupling to a tissue surface of tissue;

FIG. 15 is a perspective view of another embodiment of an electrosurgical device according to the present invention;

FIG. 16 is a close-up view of the shaft of the device of FIG. 15;

FIG. 17 is a close-up longitudinal cross-sectional view of the shaft of the device of FIG. 15;

FIG. 18 is a close-up view of the electrodes of the device of FIG. 15 with an exemplary fluid coupling to a tissue surface of tissue;

FIG. 19 is a close-up cross-sectional view of the device of FIG. 15 taken along line 19-19 with another view of a fluid coupling to a tissue surface of tissue;

FIG. 20 is a close-up view of another embodiment of the fluid outlet(s) of the device of FIG. 15;

FIG. 21 is a is a close-up view of another embodiment of the electrodes of the device of FIG. 15;

FIG. 22 is a perspective view of a distal portion of another embodiment of an electrosurgical device according to the present invention;

FIG. 23 is a perspective view of a distal portion of another embodiment of the electrosurgical device of FIG. 22 according to the present invention;

FIG. 24 is a perspective view of a distal portion of another embodiment of an electrosurgical device according to the present invention; and

FIG. 25 is a perspective view of a distal portion of another embodiment of the electrosurgical device of FIG. 24 according to the present invention.

DETAILED DESCRIPTION

Throughout the description, like reference numerals and letters indicate corresponding structure throughout the several views. Also, any particular feature(s) of a particular exemplary embodiment may be equally applied to any other exemplary embodiment(s) of this specification as suitable. In other words, features between the various exemplary embodiments described herein are interchangeable as suitable, and not exclusive. From the specification, it should be clear that any use of the terms “distal” and “proximal” are made in reference to the user of the device, and not the patient.

The invention provides systems, devices and methods to control tissue temperature at a tissue treatment site during an electrosurgical procedure, as well as shrinking, coagulating, cutting and sealing tissue against blood and other fluid loss, for example, by shrinking the lumens of blood vessels (e.g., arteries, veins). The devices may be configured, due to the narrow electrode size, to fit through a trocar down to a size as small as 5 mm.

The invention will now be discussed with reference to the figures, with FIG. 1 showing a front view of one embodiment of a system of the present invention which may include an electrosurgical unit 10 in combination with a fluid source 20 and a handheld electrosurgical device 30. In addition, FIG. 1 shows a movable cart 2 having a support member 4 comprising a hollow cylindrical post which carries a platform 6 comprising a pedestal table to provide a flat, stable surface for location of the electrosurgical unit 10.

As shown, cart 2 further comprises a fluid source carrying pole 8 having a height which may be adjusted by sliding the carrying pole 8 up and down within the support member 4 and thereafter secured in position with a set screw. On the top of the fluid source carrying pole 8 is a cross support provided with loops at the ends thereof to provide a hook for carrying fluid source 20.

As shown in FIG. 1, fluid source 20 may comprise a bag of fluid from which fluid 12 may flow through a drip chamber 14, particularly after the bag is penetrated with a spike located at the end of the drip chamber 14. Thereafter, fluid 12 may flow through flexible and compressible fluid delivery tubing 16 to handheld electrosurgical device 30. The fluid delivery tubing 16 may be made from a synthetic polymer material, such as polyvinyl chloride.

As shown in FIG. 1, the fluid delivery tubing 16 passes through pump 22. As shown, pump 22 may comprise a peristaltic pump and, more specifically, a rotary peristaltic pump. With a rotary peristaltic pump, a portion of the delivery tubing 16 may be loaded into the pump head by raising and lowering the pump head in a known manner. Fluid 12 may then be conveyed within the delivery tubing 16 by waves of contraction placed externally on the tubing 16 which may be produced mechanically, typically by rotating pinch rollers which rotate on a drive shaft and intermittently compress the tubing 16 against an anvil support. Peristaltic pumps may be particularly used, as the electro-mechanical force mechanism, here rollers driven by electric motor, do not contact the fluid 12, thus reducing the likelihood of inadvertent contamination.

In the present embodiment the fluid 12 may particularly comprise liquid saline solution, and even more particularly, normal (0.9% w/v NaCl or physiologic) saline. Although the description herein may make reference to saline as the fluid 12, other electrically conductive fluids may be used in accordance with the invention.

Additionally, while an electrically conductive fluid having an electrically conductivity similar to normal saline may be preferred, as will become more apparent with further reading of this specification, fluid 12 may also be an electrically non-conductive fluid. The use of a non-conductive fluid, while not providing all the advantage of an electrically conductive fluid, still provides certain advantages over the use of a dry electrode including, for example, reduced occurrence of tissue sticking to the electrode of device 30 and cooling of the electrode and/or tissue. Therefore, it is also within the scope of the invention to include the use of an electrically non-conductive fluid, such as, for example, deionized water.

Electrosurgical unit 10 may be particularly configured to provide both monopolar and bipolar radio-frequency (RF) power output. However, electrosurgical unit 10 may particularly include a lock out feature which prevents both monopolar and bipolar output from being activated simultaneously. Alternatively, rather than use a single electrosurgical unit 10, device 30 may be simultaneously connected to two separate electrosurgical units. For example, device 30 may be connected to a first electrosurgical unit 10 to provide monopolar power output thereto and a second electrosurgical unit 10 to provide bipolar power output thereto.

During monopolar operation of electrosurgical device 30, a first electrode, often referred to as the active electrode, may be provided with electrosurgical device 30 while a second electrode, often referred to as the indifferent or neutral electrode, may be provided in the form of a ground pad dispersive electrode located on the patient (also known as a patient return electrode), typically on the back or other suitable anatomical location. An electrical circuit may then be formed between the active electrode and ground pad dispersive electrode with electrical current flowing from the active electrode through the patient to ground pad dispersive electrode in a manner known in the art.

During bipolar operation of electrosurgical device 30, the ground pad electrode located on the patient is not required, and a second electrode providing a second electrical pole may be provided as part of the device. An alternating current electrical circuit may then be created between the first and second electrical poles of the device. Consequently, alternating current no longer flows through the patient's body to the ground pad electrode, but rather through a localized portion of tissue between the poles of device 30. As indicated above, monopolar and bipolar power may be provided from electrosurgical unit 10 as known in the art, or from separate electrosurgical units.

As shown in FIG. 1, electrosurgical device 30 may be connected to electrosurgical unit 10 via electrical cables 24 and 26. Cable 24 is shown with a plug 34 which connects to bipolar output receptacle 38 of electrosurgical unit 10, while cable 26 is shown with a plug 42 which connects to the monopolar output receptacle 46 of electrosurgical unit 10. Briefly turning to FIG. 6, when electrosurgical 10 may be used in monopolar mode, additional cable 28 may connect a ground pad dispersive electrode 48 to the ground pad receptacle 56 of the electrosurgical unit 10.

FIG. 2 shows the front panel of exemplary electrosurgical unit 10. A power switch 58 may be used to turn the electrosurgical unit 10 on and off. After turning the electrosurgical unit 10 on, an RF power setting display 60 may be used to display the RF power setting numerically in watts. The power setting display 60 may further comprise a liquid crystal display (LCD).

Electrosurgical unit 10 may further include an RF power selector 62 comprising RF power setting switches 62 a, 62 b which may be used to select the RF power setting. Pushing the switch 62 a may increase the RF power setting, while pushing the switch 62 b may decrease the RF power setting. Electrosurgical unit 10 may also include an RF power activation display 64 comprising an indicator light which may illuminate when RF power is activated, either via a handswitch on device 30 or a footswitch. Switches 62 a, 62 b may comprise membrane switches. It should be understood that while only one RF power selector 62 is shown, electrosurgical unit 10 may have two such RF power selectors with one each for monopolar and bipolar power selection.

In addition to having a RF power setting display 60, electrosurgical unit 10 may further include a fluid flow rate setting display 66. Flow rate setting display 66 may comprise three indicator lights 66 a, 66 b and 66 c with first light 66 a corresponding to a fluid flow rate setting of low, second light 66 b corresponding to a fluid flow rate setting of medium (intermediate) and third light 66 c corresponding to a flow rate setting of high. One of these three indicator lights will illuminate when a fluid flow rate setting is selected.

Electrosurgical unit 10 may further include a fluid flow selector 68 comprising flow rate setting switches 68 a, 68 b and 68 c used to select or switch the flow rate setting. Three push switches may be provided with first switch 68 a corresponding to the fluid flow rate setting of low, second switch 68 b corresponding to a fluid flow rate setting of medium (intermediate) and third switch 68 c corresponding to a flow rate setting of high. Pushing one of these three switches may select the corresponding flow rate setting of either low, medium (intermediate) or high. The medium, or intermediate, flow rate setting may be automatically selected as the default setting if no setting is manually selected. Switches 68 a, 68 b and 68 c may comprise membrane switches.

Before starting a surgical procedure, it may be desirable to prime device 30 with fluid 12. Priming may be desirable to inhibit RF power activation without the presence of fluid 12. A priming switch 70 may be used to initiate priming of device 30 with fluid 12. Pushing switch 70 once may initiate operation of pump 22 for a predetermined time period to prime device 30. After the time period is complete, the pump 22 may shut off automatically. When priming of device 30 is initiated, a priming display 72 comprising an indicator light may illuminate during the priming cycle.

An exemplary bipolar RF power output curve of electrosurgical unit 10 is shown in FIG. 3. Impedance Z, shown in units of ohms on the X-axis and output power P_(O) is shown in units of watts on the Y-axis. In the illustrated embodiment, the bipolar electrosurgical power (RF) is set to 200 watts. As shown in the figure, for an RF power setting P_(S) of 200 watts, the output power P_(O) will remain constant with the set RF power P_(S) as long as the impedance Z stays between the low impedance cut-off of 30 ohms and the high impedance cut-off of 120 ohms. Below an impedance Z of 30 ohms, the output power P_(O) will decrease as shown by the low impedance ramp. Above an impedance Z of 120 ohms, the output power P_(O) will also decrease as shown by the high impedance ramp. With respect to monopolar power output, an exemplary monopolar RF power output curve would include that of the Valleylab Force FX, either for cut or coagulation mode, hereby incorporated by reference.

Electrosurgical unit 10 may be configured such that the speed of pump 22, and therefore the throughput of fluid 12 expelled by the pump 22, is predetermined based on two input variables, the RF power setting and the fluid flow rate setting. In FIG. 4 there is shown an exemplary functional relationship of fluid flow rate Q in units of cubic centimeters per minute (cc/min) on the Y-axis, and the RF power setting P_(S) in units of watts on the X-axis. The relationship may be engineered to inhibit undesirable effects such as tissue desiccation, electrode sticking, smoke production and char formation, while at the same time not providing a fluid flow rate Q at a corresponding RF power setting P_(S) which is so great as to provide too much electrical dispersion and cooling at the electrode/tissue interface. While not being bound to a particular theory, a more detailed discussion on how the fluid flow rate interacts with the radio frequency power, modes of heat transfer away from the tissue, fractional boiling of the fluid and various control strategies may be found in U.S. Publication No. 2001/0032002, published Oct. 18, 2001, assigned to the assignee of the present invention and hereby incorporated by reference in its entirety to the extent it is consistent.

As shown in FIG. 4, electrosurgical unit 10 has been configured to increase the fluid flow rate Q linearly with an increasing RF power setting P_(S) for each of three fluid flow rate settings of low, medium and high corresponding to Q_(L), Q_(M) and Q_(H), respectively. Conversely, electrosurgical unit 10 has been configured to decrease the fluid flow rate Q linearly with a decrease RF power setting P_(S) for each of three fluid flow rate settings of low, medium and high corresponding to Q_(L), Q_(M) and Q_(H), respectively.

An electrosurgical unit similar to exemplary electrosurgical unit 10 and having detailed schematic drawings, albeit without monopolar output, may be found in U.S. Publication No. 2006/0149225, published Jul. 6, 2006, assigned to the assignee of the present invention and hereby incorporated by reference in its entirety to the extent it is consistent.

While electrosurgical unit 10 as shown above includes an attached pump 22, in other embodiments pump 22 may not be integrated with electrosurgical unit 10, but rather be separate from electrosurgical unit 10.

In still other embodiments, pump 22 may be eliminated and there may be no preset functional relationship of fluid flow rate Q versus RF power setting P_(S) stored in the electrosurgical unit 10. In such an instance, rather than the fluid flow rate Q being automatically controlled by the electrosurgical unit 10 based on the RF power setting P_(S), the fluid flow rate Q may be manually controlled, such as by the user of device 10 or another member of the surgical team, with a roller (pinch) clamp or other clamp provided with device 10 and configured to act upon and compress the tubing 16 and control flow in a manner known in the art. Exemplary fluid flow control mechanisms may be found in U.S. Publication No. 2005/0090816, published Apr. 28, 2005, assigned to the assignee of the present invention and hereby incorporated by reference in its entirety to the extent it is consistent. An example of an electrosurgical unit which does not include a pump, but may be used in conjunction with a manually operated fluid flow control mechanism on device 10, includes an electrosurgical unit such as the Valleylab Force FX.

An exemplary bipolar and/or monopolar electrosurgical device of the present invention which may be used in conjunction with electrosurgical unit 10 of the present invention is shown at reference character 30 a in FIG. 5. While various electrosurgical devices of the present invention are described herein with reference to use with electrosurgical unit 10, it should be understood that the description of the combination is for purposes of illustrating the system of the invention. Consequently, it should be understood that while the electrosurgical devices disclosed herein may be disclosed for use with electrosurgical unit 10, it may be plausible to use other electrosurgical devices with electrosurgical unit 10, or it may be plausible to use the electrosurgical devices disclosed herein with another electrosurgical unit.

As shown in FIG. 5, exemplary device 30 a includes an elongated handpiece 100 with a handle 101 comprising mating handle portions 101 a, 101 b. Handpiece 100 may be configured to enable a user of device 30 a to hold and manipulate device 30 a between the thumb and index finger like a writing instrument. Handle 101 may comprise a sterilizable, rigid, electrically insulative material, such as a synthetic polymer (e.g., polycarbonate, acrylonitrile-butadiene-styrene).

Device 30 a further includes cables 24 and 26, as shown in FIG. 1, which are connectable to electrosurgical unit 10 to provide device 30 a with bipolar and monopolar power output, respectively, from electrosurgical unit 10. As further shown in FIG. 6, cable 24 of device 30 a may comprise three insulated wire conductors 32 a, 32 b, 32 c connectable to bipolar power output receptacles 38 a, 38 b, 38 c of electrosurgical unit 10 via three banana (male) plug connectors 36 a, 36 b, 36 c. The banana plug connectors 36 a, 36 b, 36 c may be each assembled with insulated wire conductors 32 a, 32 b, 32 c within the housing of plug 34 in a known manner. On device 30 a, insulated wire conductor 32 a may be connected to a bipolar hand switch assembly 110, and insulated wire conductors 32 b and 32 c may be connected to a proximal portion of electrodes 102 a, 102 b, particularly by welding.

Electrodes 102 a, 102 b thereafter may extend through linear conduits provided by cylindrical through passages 104 a, 104 b of elongated, rigid, electrically insulative shaft 108 comprising shaft body 106. Shaft body 106 may comprise a sterilizable, rigid, electrically insulative material, such as a synthetic polymer (e.g., polycarbonate, acrylonitrile-butadiene-styrene). At the distal end of device 30, a distal portion of electrodes 102 a, 102 b having a U-shape loop extends from the passages 104 a, 104 b of elongated shaft body 106.

Cable 26 of device 30 a may comprise two insulated wire conductors 40 a, 40 b connectable to monopolar power output receptacles 46 a, 46 b of electrosurgical unit 10 via two banana (male) plug connectors 44 a, 44 b. The banana plug connectors 44 a, 44 b may be each assembled with insulated wire conductors 40 a, 40 b within the housing of plug 42 in a known manner. On device 30 a, insulated wire conductor 40 a may be connected to a monopolar hand switch assembly 112, and insulated wire conductor 40 b may be connected to a proximal portion of electrode 102 b of shaft 108. As shown wire conductors 32 b and 40 b may merge inside handle 100 and share the same attachment location to electrode 102 b.

When device 30 a is used in monopolar mode, an additional cable 28 may be utilized to connect a ground pad dispersive electrode 48, which is attached to the patient, to the electrosurgical unit 10 comprising wire conductor 50 and plug 52 at the end thereof having plug connector 54 which connects to the ground pad receptacle 56.

Hand switch assemblies 110 and 112 may comprise push buttons 114 and 116, respectively, which overlie domed switches on a platform comprising a printed circuit board, with the construction and wiring of the hand switch assemblies 110 and 112 known in the art. Upon depression of push buttons 114 or 116, a domed switch beneath the push button forms a closed circuit which is sensed by electrosurgical unit 10, which then provides bipolar or monopolar power, respectively. Exemplary hand switches may be found in U.S. Publication No. 2006/0149225, published Jul. 6, 2006, and U.S. Publication No. 2005/0090816, published Apr. 28, 2005, which are assigned to the assignee of the present invention and are hereby incorporated by reference in there entirety to the extent they are consistent.

As shown FIG. 7, during use of device 30 a, fluid 12 from fluid source 20 may be communicated through a tubular fluid passage provided by various structures. In the present embodiment, fluid 12 from the fluid source 20 is first communicated through lumen 18 of delivery tubing 16. Fluid 12 may then flow through lumen 120 of a special pump tubing segment 118 configured to operate specifically with the peristaltic pump 22, which may be spliced in between portions of delivery tubing 16 and connected thereto using barbed fluid line connectors 122 at each end thereof.

Within handle 101 of device 30 a, fluid delivery tubing 16 may be connected to the inlet branch of a Y-splitter 124, which thereafter provides two outlet branches which may be connected to the proximal end portion of delivery tubing segments 128 a, 128 b. A distal end portion of the delivery tubing segments 128 a, 128 b may be connected to shaft body 106 by being inserted into cylindrical receptacles 132 a, 132 b (counter bores) of shaft body 106. Fluid 12 then may flow through lumens 130 a, 130 b of delivery tubing segments 28 a, 128 b and into tubular passages 134 a, 134 b formed in shaft body 106. Fluid 12 may then be expelled from fluid delivery outlets 136 a, 136 b at the distal end of shaft body 106.

Alternatively, as shown in FIG. 8, fluid delivery tubing 16 may be inserted directly into receptacle 132 of shaft body 106. Fluid 12 then may flow through passage 134 before branching into passages 134 a, 134 b within shaft body 106 and being expelled from fluid delivery outlets 136 a, 136 b. Also, alternatively, a single fluid outlet 136 may be located between the electrodes 102 a, 102 b, as shown in FIG. 10, in which case outlets 136 a, 136 b may be omitted.

FIG. 9 provides a close-up view of shaft body 106, U-shaped electrodes 102 a, 102 b and fluid delivery outlets 136 a, 136 b. As shown, U-shaped electrodes 102 a, 102 b may be arranged to provide two fixed, laterally and spatially separated (by empty space) electrode tips which may be configured as mirror images in size and shape, and may have a blunt, rounded distal end which provides a smooth continuous surface (which is devoid of points or edges) to treat tissue. As shown, U-shaped electrodes 102 a, 102 b may be coplanar (i.e. in the same plane).

U-shaped electrodes 102 a, 102 b, which are adjacent the distal end 138 of shaft body 106, may each comprise lateral longitudinal segments 140 a, 140 b and medial longitudinal segments 142 a, 142 b which extend distally from the distal end 138 of shaft body 106 and are proximal to arcuate distal segments 144 a, 144 b. It should be understood that while the electrodes 102 a, 102 b have been described as having various segments, the description is aimed to provide orientation of such relative to the device, and not that the electrodes 102 a, 102 b are necessarily provided from separately formed individual segments which have been joined together. To the contrary, each electrode 102 a, 102 b may be particularly formed from a single continuous member, such as a single continuous piece of wire described in greater detail below.

As shown, the arcuate distal segments are continuously arcuate from one longitudinal segment to the other longitudinal segment without any interruptions, and more particularly may be semicircular with a radius of 180 degrees. Also as shown, fluid delivery outlet 136 a is located between longitudinal segments 140 a, 142 a, and fluid delivery outlet 136 b is located between longitudinal segments 140 b, 142 b. In this manner, fluid 12 expelled from fluid delivery outlets 136 a, 136 b may better form a fluid membrane between longitudinal segments 140 a, 142 a and 140 b, 142 b, respectively, as discussed in greater detail below.

Returning to FIG. 7, the lateral longitudinal segments 140 a, 140 b extend through the length of shaft body 106. However, the medial longitudinal segments 142 a, 142 b are retained in (e.g. interference/friction fit) and extend from a receptacles (blind bores) 146 a, 146 b formed in the distal end of shaft body 106. As shown in the figures, lateral longitudinal segments 140 a, 140 b and medial longitudinal segments 142 a, 142 b are all parallel and coplanar (in the same plane).

Electrodes 102 a, 102 b may particularly be formed from single strand, metal (particularly stainless steel) wire. Each electrode 102 a, 102 b may have an overall (exposed) length L in the range of and any increment between 4 mm to 15 mm, and more particularly 6 mm to 12 mm. Each electrode 102 a, 102 b may have a width W in the range of and any increment between 1 mm to 4 mm, and more particularly 2 mm to 3 mm.

As shown in FIG. 10, the wire may be cylindrical and have a circular cross-sectional profile with a cross-section thickness, here diameter, in a range of and any increment between 0.1 mm to 1.5 mm, and more particularly 0.5 mm to 1 mm, and even more particularly 0.6 to 0.75 mm.

With respect to spacing, the spatial gap separation GS between electrodes 102 a, 102 b may be in the range of and any increment between 0.1 mm to 3 mm, and more particularly 0.5 mm to 2 mm, and even more particularly 0.75 mm to 1.5 mm. The spacing between the medial 142 a, 142 b and lateral segments 140 a, 140 b of each electrode 102 a, 102 b may be in a range of and any increment between 0.1 mm to 3 mm, and more particularly 0.5 mm to 2 mm, and even more particularly 0.75 mm to 1.5 mm.

As shown in FIG. 11, at least a portion of the length of lateral longitudinal segment 140 b′ may be shaped, particularly from circular wire by grinding or sanding, as to have a cross-sectional profile with opposing sides 150 b/152 b which converge laterally to provide a wedge shaped blade portion 154 b on the perimeter which terminates in a linear lateral cutting edge 156 b which extends longitudinally along the length of longitudinal segment 140 b′. As shown, in alternative embodiments, any of the remaining longitudinal segments 140 a′, 142 a′ or 142 b′ may have the same cross-sectional profile as segment 140 b′.

As shown in FIG. 11, blade portion 154 b narrows as the opposing sides 150 b/152 b approach cutting edge 156 b. More particularly, the sides 150 b/152 b of blade portion 154 b are planar. However, in other embodiments, sides 150 b/152 b may be concave or convex.

As shown in FIG. 12, at least a portion of the length of lateral longitudinal segment 140 b may be shaped, particularly from circular wire by grinding or sanding, as to have a profile with opposing sides 150 b/152 b which are substantially parallel and terminate in linear lateral cutting edge 156 b which extends longitudinally along the length of longitudinal segment 140 b. As shown, in alternative embodiments, any of the remaining longitudinal segments 140 a, 142 a or 142 b may have the same profile as segment 140 b. Here, segment 140 has a polygonal profile, and more particularly a rectangular profile.

For the electrodes 102 a, 102 b shown in FIGS. 11 and 12, lateral cutting edge 156 b may be particularly configured to cut tissue electrosurgically in the presence of monopolar radio frequency energy from electrosurgical unit 10 as to provide an electrosurgical cutting edge, but without any fluid 12 being provided from fluid source 20. However, in other embodiments, lateral cutting edge 156 b may be configured to cut tissue with fluid 12 being provided simultaneously from device 30 a, or be configured to cut tissue mechanically (sharpened) without electrosurgical energy. Referring now to FIG. 13, device 30 a may be used to cut tissue by applying cutting edge 156 b of electrode 102 b to tissue 200, and repeatedly moving the electrode 102 b along a desired incision or resection line in the tissue to form the depicted crevice.

While cutting edge 156 b may be particularly configured to cut tissue with monopolar RF energy and without fluid 12 being expelled from device 30 a, arcuate distal end segments 144 a, 144 b may be particularly configured to slide or otherwise move across a tissue surface in the presence of bipolar radio frequency energy from electrosurgical unit 10 and fluid 12 from the fluid source 20.

As shown in FIG. 14, one way in which device 30 a may be used as a bipolar device is with the longitudinal axis of electrodes 102 a, 102 b vertically orientated, and the arcuate distal segments 144 a, 144 b of electrodes 102 a, 102 b laterally spaced adjacent tissue surface 202 of tissue 200. When device 30 a is used in this manner, electrodes 102 a, 102 b may be connected to electrosurgical unit 10 and receive bipolar radio frequency energy which forms an alternating current electrical field in tissue 200 located between electrodes 102 a, 102 b. In the presence of alternating current, the electrodes 102 a, 102 b alternate polarity between positive and negative charges with current flow from the positive to negative charge. Without being bound to a particular theory, heating of the tissue is performed by electrical resistance heating.

Fluid 12, in addition to providing an electrical coupling between the device 30 a and tissue 200, lubricates surface 202 of tissue 200 and facilitates the movement of electrodes 102 a, 102 b across surface 202 of tissue 200. During movement of electrodes 102 a, 102 b, electrodes 102 a, 102 b typically slide across the surface 202 of tissue 200. Typically the user of device 30 a slides electrodes 102 a, 102 b across surface 202 of tissue 200 back and forth with a painting motion while using fluid 12 as, among other things, a lubricating coating. Preferably the thickness of the fluid 12 between the arcuate distal segments 144 a, 144 b of electrodes 102 a, 102 b and surface 202 of tissue 200 at the outer edge of couplings 204 a, 204 b is in the range of 0.05 mm to 1.5 mm. Also, in certain embodiments, the arcuate distal segments 144 a, 144 b of electrodes 102 a, 102 b may contact surface 202 of tissue 200 without any fluid 12 in between.

As shown in FIG. 14, fluid 12 expelled from fluid outlets 136 a, 136 b may flow distally on electrodes 102 a, 102 b in the form of droplets 208 a, 208 b or as a membrane 210 a, 210 b extending across the U-shaped apertures 160 a, 160 b and bridging between longitudinal segments 140 a, 142 a and 140 b,142 b of electrodes 102 a, 102 b. As shown in FIG. 14, droplets 208 a, 208 b may form at varying times from fluid 12 expelled from fluid outlets 136 a, 136 b. Also, fluid 12 may be expelled in varying quantity from each of the fluid outlets 136 a, 136 b, depending on, for example, device orientation, pressure, flow rate and varying fluid outlet sizes. With use of device 30 a, the physical characteristics of the droplets 208 a, 208 b and the membranes 210 a, 210 b may also vary due to changes in the surface finish of the electrodes 102 a, 102 b. For example, the membranes 210 a, 210 b may form a meniscus type curvature at either end thereof as they progress distally along electrodes 102 a, 102 b.

Fluid 12 in the form of membranes 210 a, 210 b bridging apertures 160 a, 160 b may offer certain advantages over droplets 208, 208 b as the membranes 210 a, 210 b, after flowing distally along the longitudinal segments of electrodes 102 a, 102 b, may be more evenly distributed over arcuate distal segments 144 a, 144 b of electrodes 102 a, 102 b, to then form fluid couplings 204 a, 204 b. Also, membranes 210 a, 210 b may exhibit better retention to electrodes 102 a, 102 b while flowing distally along electrodes 102 a, 102 b and not fall off as may be the situation for droplets 208 a, 208 b.

As shown in FIG. 14, fluid couplings 204 a, 204 b may particularly comprise discrete, localized webs and more specifically comprise triangular shaped webs of fluid 12 between surface 202 of tissue 200 and electrodes 102 a, 102 b. When the user of electrosurgical device 30 a places electrodes 102 a, 102 b at a tissue treatment site and moves electrodes 102 a, 102 b across the surface 202 of the tissue 200, fluid 12 is expelled from fluid outlets 136 a, 136 b around the surfaces of electrodes 102 a, 102 b and onto the surface 202 of the tissue 200 via couplings 204 a, 204 b. At the same time, RF electrical energy, shown by electrical field lines 206, is provided to tissue 200 at tissue surface 202 and below tissue surface 202 into tissue 200 through fluid couplings 204 a, 204 b. In the foregoing manner, device 30 a may be used to seal tissue against blood and other fluid loss.

Thus, while cutting edge 156 b may be particularly configured to cut tissue with monopolar RF energy and without fluid 12 being expelled from device 30 a, arcuate distal end segments 144 a, 144 b may be particularly configured to slide or otherwise move across a tissue surface in the presence of bipolar radio frequency energy from electrosurgical unit 10 and fluid 12 from the fluid source 20.

Another embodiment of device 30 is shown in FIGS. 15-18 as device 30 b. As shown, rather the U-shaped electrodes being spaced side-by-side as with embodiment 30 a, the U-shaped electrodes are arranged such that the perimeter of U-shaped electrode 102 a is surrounded by U-shaped electrode 102 b, with U-shaped electrode 102 a located within the U-shaped aperture 160 b defined by electrode 102 b. In this manner, the two longitudinal segments 140 a, 142 a of electrode 102 a are now medial to the two longitudinal segments 140 b, 142 b of electrode 102 b. Vice-versa, the two longitudinal segments 140 b, 142 b of electrode 102 b are now lateral to the two longitudinal segments 140 a, 142 a of electrode 102 a. As compared with device 30 a, the electrode configuration of device 30 b may be somewhat narrower, which may make device 30 b less intrusive than device 30 a and afford device 30 b greater access to more confined locations with greater visibility.

As shown arcuate distal segments 144 a, 144 b of electrodes 102 a, 102 b may be concentric. In other words, arcuate distal segments 144 a, 144 b may have a common center point CP. As shown, similar to embodiment 30 a, U-shaped electrodes 102 a, 102 b are coplanar (in the same plane). Also similar to embodiment 30 a, longitudinal segments 140 a, 140 b and longitudinal segments 142 a, 142 b are all parallel and coplanar (in the same plane). Also similar to embodiment 30 a, U-shaped electrodes 102 a, 102 b may have the same cross-sectional profiles as set forth in FIGS. 10-12. In this manner, electrode 102 b may still include cutting edge 156 b particularly configured to cut tissue with monopolar RF energy and without fluid 12 being expelled from device 30 b.

As shown in FIGS. 18-19, one way in which device 30 b may be used as a bipolar device is with the longitudinal axis of electrodes 102 a, 102 b substantially horizontally orientated. When device 30 a is used in this manner, electrodes 102 a, 102 b may be connected to electrosurgical unit 10 and receive bipolar radio frequency energy which forms an alternating current electrical field in tissue 200 located between electrodes 102 a, 102 b and fluid 12 provided from device 30 b.

Fluid 12, in addition to providing an electrical coupling between the device 30 a and tissue 200, lubricates surface 202 of tissue 200 and facilitates the movement of electrodes 102 a, 102 b across surface 202 of tissue 200. As shown in FIGS. 18-19, fluid 12 expelled from fluid outlet 136 may form fluid couplings 204.

As shown in FIG. 19, fluid couplings 204 may particularly comprise localized webs and more specifically comprise triangular shaped webs of fluid 12 between surface 202 of tissue 200 and electrodes 102 a, 102 b. When the user of electrosurgical device 30 b places electrodes 102 a, 102 b at a tissue treatment site and moves electrodes 102 a, 102 b across the surface 202 of the tissue 200, fluid 12 is expelled from fluid outlet 136 around the surfaces of electrodes 102 a, 102 b and onto the surface 202 of the tissue 200 via couplings 204. At the same time, RF electrical energy, shown by electrical field lines 206, is provided to tissue 200 at tissue surface 202 and below tissue surface 202 into tissue 200 through fluid couplings 204. In the foregoing manner, device 30 b may be used to seal tissue against blood and other fluid loss.

As shown in FIGS. 15-19, fluid outlet 136 may be located between longitudinal segments 140 a, 142 a of electrodes 102 a. As shown in FIG. 20, a fluid outlet 136 may be located between longitudinal segments 142 a of electrode 102 a and longitudinal segment 142 b of electrode 102 b. A fluid outlet 136 may also be located between longitudinal segments 140 a of electrode 102 a and longitudinal segment 140 b of electrode 102 b. In various embodiments, any fluid outlet 136 may be used individually or in combination with any other of fluid outlet(s) 136 as shown. For example, one or both of the fluid outlets 136 shown in FIG. 20 may be used in combination with the fluid outlet 136 shown in FIGS. 15-19.

For the embodiment of device 30 b shown in FIGS. 15-19, outer electrode 102 b has the same cross-sectional profile with a thickness (here diameter) equal to the diameter of inner electrode 102 a. However, as shown in FIG. 21, outer electrode 102 b may have a smaller cross-sectional profile with a thickness (here diameter) less than that of inner electrode 102 a, to better facilitate cutting with a narrower incision, as well as better conforming to the tissue surface during sealing tissue, particularly by deforming when a slight pressure is applied by the user.

In another embodiment of the device 30, shown as device 30 c in FIG. 22, electrode 102 a may comprise a single longitudinal segment 166 rather than having a U-shape. Similar to device 30 b, the perimeter of electrode 102 a is surrounded by U-shaped electrode 102 b, with electrode 102 a located within the U-shaped aperture 160 b defined by electrode 102 b. In this manner, the longitudinal segment 166 of electrode 102 a is medial to the two longitudinal segments 140 b, 142 b of electrode 102 b. Vice-versa, the two longitudinal segments 140 b, 142 b of electrode 102 b are lateral to longitudinal segment 166 of electrode 102 a. As compared with device 30 b, the electrode configuration of device 30 c may be somewhat narrower, which may make device 30 c less intrusive than device 30 b and afford device 30 c greater access to more confined locations with greater visibility.

As shown, similar to embodiments 30 a and 30 b, electrodes 102 a, 102 b are coplanar (in the same plane). Also similar to embodiments 30 a and 30 b, longitudinal segment 166 and longitudinal segments 142 a, 142 b are all parallel and coplanar (in the same plane). Also similar to embodiments 30 a and 30 b, electrodes 102 a, 102 b may have the same cross-sectional profiles as set forth in FIGS. 10-12. In this manner, electrode 102 b may still include cutting edge 156 b particularly configured to cut tissue with monopolar RF energy and without fluid 12 being expelled from device 30 c.

As shown in FIG. 22, a fluid outlet 136 may be located between longitudinal segment 166 of electrode 102 a and longitudinal segment 142 h of electrode 102 b. A fluid outlet 136 may also be located between longitudinal segment 166 of electrode 102 a and longitudinal segment 140 b of electrode 102 b. Device 30 c may be used similar to device 30 b to cut and seal tissue as described herein. In an alternative embodiment, as shown in FIG. 23, an electrical insulator 164, such as formed from a synthetic polymer (e.g. acetal), may be located between the two electrodes 102 a, 102 b, and particularly between the distal end of electrode 102 a and the arcuate segment 144 b of electrode 102 b to better hold the position of the electrodes 102 a, 102 b relative to one another. Aperture 160 b′ is also shown.

In another embodiment of the device 30, shown as device 30 d in FIG. 24, electrode 102 a may take the form of a longitudinally orientated elongated blade shaped member 170 with a planar body, such as may be provided by a flattened portion of metal (e.g. stainless steel) tubing 172 which has been inserted in tubular passage 134 of shaft body 106. In this manner, lumen 18 of fluid delivery tubing 16 may be in fluid communication with lumen 174 of metal tubing 172 such that fluid 12 may be expelled from fluid delivery outlet 136 adjacent the opposing sides 178, 180 of the blade member 170 as defined by the tubing 172, and insulated wire conductor 32 c may be connected to a proximal portion of the tubing, particularly by welding. With regards to dimensions, blade member 170 of electrode 102 a may have a length in the range of and any increment between 4 mm to 15 mm, and more particularly 6 mm to 12 mm. Blade 170 may have a width in the range of and any increment between 1 mm to 4 mm, and more particularly 2 mm to 3 mm.

Similar to devices 30 b and 30 c, the perimeter of electrode 102 a is surrounded by U-shaped electrode 102 b, with electrode 102 a located within the U-shaped aperture 160 b defined by electrode 102 b. In this manner, the blade member 170 of electrode 102 a is medial to the two longitudinal segments 140 b, 142 b of electrode 102 b. Vice-versa, the two longitudinal segments 140 b, 142 b of electrode 102 b are lateral to blade member 170 of electrode 102 a.

As shown, similar to embodiments 30 a-30 c, electrodes 102 a, 102 b are coplanar (in the same plane). Also similar to embodiments 30 a-30 c, blade member 170 and longitudinal segments 142 a, 142 b are all parallel and coplanar (in the same plane). Also similar to embodiments 30 a-30 c, electrode 102 b may have the same cross-sectional profiles as set forth in FIGS. 10-102. In this manner, electrode 102 b may still include cutting edge 156 b particularly configured to cut tissue with monopolar RF energy and without fluid 12 being expelled from device 30 d.

The perimeter 176 of blade member 170 from one (top) side 178 to the other (bottom) side 180 may be semi-circular as shown, or may have an narrow or pointed edge 156 b as shown in either of FIG. 11 or 12. Also, as shown the distal end 182 of blade member 170 is arcuate, and more particular semi-circular, across the width of the blade member 170. Also as shown, the arcuate distal segment 144 b of electrode 102 b and the arcuate distal end 182 of blade member 170 may be concentric. As shown in FIG. 25, the fluid outlet 136 may be orientated parallel with the longitudinal perimeter of the blade member 170 to better feed fluid 16 directly into aperture 160 b.

As compared to devices 30 b and 30 c, device 30 d and particularly electrode 102 b may be expected to cut tissue in a similar manner. With regards to sealing tissue, device 30 d may be able to seal larger areas of tissue from blood and other fluid loss by having an increased surface area of electrode 102 a as provided by blade member 170.

Device 30 and the various embodiments disclosed herein, such as 30 a-30 d, may be particularly useful to surgeons to achieve hemostasis after cutting through soft tissue, as part of hip or knee arthroplasty. The electrodes 102 a, 102 b of device 30 may be moved with a painting motion over the raw, oozing surface 202 of tissue 200 to seal the tissue 200 against bleeding, or focused on individual larger bleeding vessels to stop vessel bleeding. As part of the same or different procedure, device 30 may be useful to stop bleeding from the surface of cut bone, or osseous, tissue as part of any orthopaedic procedure that requires bone to be cut. Device 30 may be particularly useful for use during orthopedic knee, hip, shoulder and spine procedures. Additional discussion concerning such procedures may be found in U.S. Publication No. 2006/0149225, published Jul. 6, 2006, and U.S. Publication No. 2005/0090816, published Apr. 28, 2005, which are assigned to the assignee of the present invention and are hereby incorporated by reference in there entirety to the extent they are consistent.

Device 30, and the various embodiments disclosed herein, such as 30 a-30 d, may be particularly useful as non-coaptive devices that provide cutting of tissue, as well as coagulation, hemostasis and sealing of tissue to inhibit blood and other fluid loss during surgery. In other words, grasping of the tissue is not necessary to shrink, coagulate, cut and seal tissue against blood loss, for example, by shrinking collagen and associated lumens of blood vessels (e.g., arteries, veins) to provided the desired hemostasis of the tissue. Furthermore, due to the configuration of the electrodes, the electrodes may be easily bent by a user of the devices as needed. The electrodes may also be used for other functions, such as providing a spoon like platform for scooping of tissue, such as an abnormal tissue mass (e.g. cancer). Furthermore, the control system of the electrosurgical unit 10 is not necessarily dependent on tissue feedback such as temperature or impedance to operate. Thus, the control system of electrosurgical unit 10 may be open loop with respect to the tissue which simplifies use.

As established above, device 30 of the present invention inhibit such undesirable effects of tissue desiccation, electrode sticking, char formation and smoke generation, and thus do not suffer from the same drawbacks as prior art dry tip electrosurgical devices. The use of the disclosed devices can result in significantly lower blood loss during surgical procedures. Such a reduction in blood loss can reduce or eliminate the need for blood transfusions, and thus the cost and negative clinical consequences associated with blood transfusions, such as prolonged hospitalization.

While a preferred embodiment of the present invention has been described, it should be understood that various changes, adaptations and modifications can be made therein without departing from the spirit of the invention and the scope of the appended claims. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents. Furthermore, it should be understood that the appended claims do not necessarily comprise the broadest scope of the invention which the Applicant is entitled to claim, or the only manner(s) in which the invention may be claimed, or that all recited features are necessary.

All publications and patent documents cited in this application are incorporated by reference in their entirety for all purposes to the extent they are consistent. 

What is claimed:
 1. An electrosurgical device having less than three electrodes, the device comprising: a handle; a shaft distal to the handle having a longitudinal axis and a distal end; a first electrode and a second electrode adjacent the distal end of the shaft, each electrode having a proximal portion, the first electrode coplanar with the second electrode and comprising a wire electrode having a U-shape which surrounds a perimeter of the second electrode and is spaced from the second electrode by an aperture, and wherein the U-shape of the first electrode is substantially situated in a plane that is substantially parallel with the longitudinal axis of the shaft; at least one fluid outlet, wherein the at least one fluid outlet is s aced from said first electrode; and wherein the proximal portions of the first and second electrodes are fixed relative to the distal end of the shaft.
 2. The device of claim 1 wherein: the second electrode comprises a wire electrode having a linear segment.
 3. The device of claim 1 wherein: the second electrode comprises a wire electrode having a U-shape.
 4. The device of claim 1 wherein: the second electrode comprises a blade shaped member.
 5. The device of claim 1, wherein the first and second electrodes do not include any outlet for fluid.
 6. The device of claim 1 wherein the at least one fluid outlet is separate from said first electrode and said second electrode.
 7. The device of claim 1 wherein: the first electrode and the second electrode are formed from metal wire.
 8. The device of claim 7 wherein: the metal wire is single strand wire.
 9. The device of claim 7 wherein: the metal wire is circular wire.
 10. The device of claim 7 wherein: the metal wire is stainless steel wire.
 11. The device of claim 1 wherein: the at least one fluid outlet is located at a distal end of the shaft.
 12. The device of claim 1 wherein: the electrodes are substantially coplanar.
 13. The device of claim 1 wherein: the device is configured to operate as a bipolar device and as a monopolar device. 